v3.25.2
Other equity - Summary of Hedge Reserve (Detail) - Hedge reserve
₨ in Millions, $ in Millions
12 Months Ended
Mar. 31, 2025
INR (₨)
Mar. 31, 2025
USD ($)
Mar. 31, 2024
INR (₨)
Mar. 31, 2023
INR (₨)
Disclosure Of Detailed Information About Reserve Of Cash Flow Hedges Of Equity [line Items]        
Beginning balance ₨ (1,867)   ₨ (618) ₨ (1,328)
OCI for the year (97)   (2,205) 861
Attributable to non-controlling interests (53)   129 (151)
Amount transferred to property, plant and equipment 1,427   827  
Ending balance ₨ (590) $ (7) ₨ (1,867) ₨ (618)